To illustrate the "3:1 Rule" the attached sketch depicts a squad size element (9 individuals) defending against a threat force consisting of three Squads (27 individuals). The following threat narrative depicts the pictured attack. "Support Element (1xSquad) suppresses enemy forces on the OBJ to prevent the concentration of fire on the assault element, on order assist with actions on the OBJ. The ASLT Support Element (1xSquad) establishes an intermediate support position to suppress defenders closest to the breach, on order assaults through the breach to secure the OBJ. ASLT Breach Element (1xSquad) reduces wire obstacle and secures the far side of the breach."
The 3:1 rule can be altered if the attacking force has a significant benefit over the defender in one of the following areas: firepower, equipment, training, moral and strength of the defense (Hasty Defense vs. Deliberate Defense).